Recovery of proteids from waste liquors of the hide-treating art



C. L. PECK.

RECOVERY 0F PROTETDS FROM WASTE LIQUORS 0F THE HIDE TREATING ART.

APPLTCATION FILED JANv 6- T920.

UNITED STATES PATENT oFFicE.

UHARLES LEE PECAK, OF NEW YORK, N. Y., ASSIGNOR TO THE DORR COMPANY, OFNEW "YORK, N. Y., A CORPORATION OF DELAWARE.

RECOVERY 0F PROTEIS FROM WASTE LIQUORS OF THE HIDE-TREATING ART.

Specification of Letters Patent.

Patented July 27, 1920.

V@riginal application lcd .'luly 2Q, 1918, Serial No. 245,854. Dividedand thisy application tiled January 6, 1920. Serial No. 349,791.

To all whom t may concern.'

Be it known that l, CHARLES LEE Pnox, a citizen of the United States,residing at N ew York city, in the county of New York, State of NewYork, have invented certaln new and useful improvements in the Recoveryof Proteids from 1Waste Liquors of the Hide-Treating Art; 'and l dohereby de- Clare the following to be a full, clear, and exactdescription of the invention, such'as will enable others skilled in theart to which it appertains to make and use the same.

In vmy application for Letters latent of the United States, Serial No.219,981,1iled March 2, 1918, is set forth a method for the recovery ofWater-insoluble non-putrescible proteids from the waste liquors of thehidetreating art. Such waste liquors of the hide-treating art (say fromthe hide cleansing process or from the hide-glue process, preliminary totanning of the hide) contain proteid matter and linie salts.

The method described in lsaid application consists in first separatingsuch liquors by sedimentationinto an eihuent, carrying proteids partlyin solution and partly in suspension, and a sludge containing causticlime and other calcium salts, hair, leshings, and fragments of hidematerial together with fatty or greasy material and som-e sand and otherforeign' matter. The euent is then treated'with a waste liquor efliuentfrom the tanning process, :whereupon the proteids are precipitated as asludge insoluble in water.

After the efliuents have been taken over from the proteid sludge andfrom the lime sludge, both sludges still contain a considerable quantityof moisture, a portion of which it is desirable to eliminate, from oneor the other, or from both, before admixing them in the next step of theprocess; it being desirable that the mixture contain as little as sayet() to 50% of moisture, so that it may seein almost dry. Thus, forinstance, the desired reduction in the moisture content 'of mixture maybe cheaply and effectively produced by exposing the proteid sludge in arelatively thin layer to the drying action of the open air, and thenmixing with it the lime sludge, in the proportions below given, so as tohave a total moisture content, as low as is feasible (say from 40% "(51050%) so that the mixture seems almost ln general, a mixture made up of100 l'parts by Weight of proteid sludge (dried to a moisture content ofsay 25%) and 50 parte by weight of lime sludge (having a moisturecontent of say 70%) will present suitable proportions for the purposesof the invention, that is to say, will constitute a mixture whereinthere is present and distributed throughout tlie, mass a sufficientquantity of 'the calcium salts to react eiliciently with the proteidspresent in the mixture. Heat facilitates the reaction, and, upon raisingthe temperature of the mass to the boiling of water, it is found that aconsiderable proportion of the proteids is made water-soluble, so thatthe portion thus converted is immediately available as a fertilizer,Without further treatment.

The product resulting from. the reaction, 1n addition to itsavailability, asidescribed,

vas a fertilizer, is rendered non-putrescible by continuing theapplication of heat thereto for a sufficient length of time and at asuiiciently high degree to not only dry it thoroughly, but to destroythe bacteria presentb A special characteristic of the invention is thatit permits the utilization of the lime sludge, not only for the recoveryof the fertilizer values contained therein,but also as a source of limein a caustic condition for reaction with the proteid sludge.

ln the accompanying drawing is shown a flow sheetl indicatingdiagrammatically the steps of the process. ln this drawing, A indicatesthe sedimentation tank wherein the Waste liquors from the hide-treatingart are received and wherein their lime sludge is separated from thesupernatent eiiiuent..

B indicates the tank or cistern for. the storage and sedimentation ofthe waste liquors from the tanning process. C indicates the reactiontank or cistern wherein the combined efluentsfrom thetanlrs or cisterneA and B are received andwherein the proteids-held in solution and insuspension in the effluent from tank A are recovered as a proteid sludge,or precipitate insoluble in water. D indicatesthe apparatus l(of anysuitable type, not shown) in which the mix.-

ture of the sludges is heated and eventually dried.

It will be understood that some of the advantages of the invention maybe obtained by substituting caustic lime for the lime sludge in thetreatment of the precipitated proteids, or by substituting (in Whole orin part) a sludge containing caustic lime, but obtained from some othersource than the Waste liquors of the lime process of the hide treatingart. These Asubstitutions I regard as Within the broader scope of theinvention, although they obviously lack the more specific advantages,hereinbefore recited, incident to the use of the sludge from thehide-treating art.

Nhat I claim is:

l. lThe method of recovering, from the Waste liquors of the lime processof the hide-treating art, material available for use as a fertilizer,which consists in separating said liquors into a sludge and an eliluent,precipitating the proteidscontained in said effluent by subjecting themto the action of the Waste liquors from the tanning process,

and then heating the precipitated proteids yin the presence of causticlime; substantially as described.

2. The method of recovering, from the waste liquors of the limeprocessof the hide-- treating art,` material available for use as afertilizer, which consists in separating'said liquors into a sludge andan effluent, precipitating the proteids contained in said effluent bysubjecting them to the action of the waste liquors from the tanningprocess, and then heating the precipitated proteids in admixtu're withysaid sludge; substantially as described.

In testimony whereof I affix my signature.

CHARLES LEE PECK.

